Manufacture of footwear



June 27, 1944. F DAWSON MANUFACTURE oF FOOTWEAR Filed June 26, 1945 H. EUsa/Wahr vfianza/*afar 2&6@ azolsan/ y gm 52 Patented June 27, 1944MANUFACTURE F FOOTWEAR Fred Dawson, West Roxbury, Mass., assignor toCompo Shoe Machinery Corporation, Boston, Mass., a corporation ofDelaware Application June 26, 1943, Serial No. 492,391

(Cl. llt- 142) Claims.

This invention relates to shoes and their manufacture and relates moreparticularly to the propiece did not extend across the full width of theshank and there were voids between the shoe bottom and portions of theshank piece resulting in undesired movement under pressure', of the shoearch.

This invention provides plastic shank pieces for cemented shoes whichare curved and owed under the influence of the heat and pressure appliedduring the cementing of the soles to the shoes,` to iiow into allcrevices and voids for filling same and to conform to the shape of thelasts for forming smooth permanent arches. l

This invention is particularly applicable to shoes cemented byelectrostatic energy as disclosed in the E. C. Pitman Patent No.2,087,480 since the plastic shank pieces may be made of materials havingthe same melting time as the cements used for cementing the solos or maybe made of the same material as the cements.

An object of the invention is to mould a plastic shank piece in acemented shoe in the same operation which applies heat and pressure forcementing the sole to the shoe.

Another object of the invention is to provide improved shank pieces forshoes.

Other and more deilnite objects of the invention are to utilizeelectrostatic energy provided for melting the cement for cementing solesto shoes, for melting a plastic shank piece, and to utilize the pressureprovided ior pressing a sole to be cemented against the shoe bottom. formoulding the melted plastic shank piece to the shape of the last.

The invention will now be described with reference to the drawing, o!which:

Fig. 1 is a plan view looking at the bottom of a shoe before the sole isapplied, with a plastic shank piece embodying this invention in placeupon the shoe bottom prior to the sole attaching operation:

Fig. 2 is a side elevation oi the shoe of Fig. l

and illustrates additionally a portion of the outsole which is tobecemented to the shoe;

Fig. 3 is a sectional view taken along the lines 3 2 of Fig. 2;

Fig. 4 is a view similar to Fig. 3 illustrating the plastic shank pieceafter it has been heated and moulded; and

Fig. 5 is a view of a press which may be used for attaching the sole to,and for moulding the plastic shank piece of, the shoe of Figs. 1 and 2.

The shoe illustrated has the upper ill tacked at I l as is usual to theheel end of the insole l while the forepart and shank portions of theupper may be lasted to the insole by an adhesive. The welt i2 isstitched at i3 in usual manner to the upper and the forepart of the shoebottom is illled with the usual cork compound. While the shoeconstruction illustrated is of the pre-welt" type other constructionssuch as Goodyear Welt" or McKay lasted uppers with er without a weltwould be suitable.

The plastic shank piece il is attached to the insole l as by tacks i6.'I'he shank piece Il has. as illustrated by Fig. 3, a radius ofcurvature substantially less than the shoe bottom and the strip il maybe within the arc of the curved shank piece for maintaining itscurvature when pressure is applied.

The sole i9 to be cemented to the shoe is then placed upon the bottom ofthe shoe with cement applied between the sole and bottom as disclosed insaid Pitman patent and the assembled shoe placed in the press 20 asillustrated by Fig. 5.

The press 20 is of the type disclosed in the John F. Smith Patent No.2,109,323 and has the pad 2l against the sole of the shoe, which isinilated by an operator to press the sole tightly against the shoebottom as disclosed in said Smith patent.

The high frequency oscillator 22 is connected to a metal bottom on thelast 23 serving as an electrode, and to an electrode on the pad 2i asalso disclosed in said Smith patent.

Following the application of the pressure upon the shoe bottom by theinflation of the pad 2l, the electric energy from the oscillator 22 isapplied to the electrodes whereupon heat is generated in the cementbetween the sole and the shoe bottom and in the plastic shank piece il.

The shank piece melts and flows to fill up the space between the inneredges of the welt as illustrated by Fig. 4 and forms a smooth curvedsurface conforming exactly to the shape of the shank portion of thelast. When cooled the plastic hardens and is bonded to the shoe bottom;to the sole and to the cement used for ceinenting the sole. Due to theflowing of the plastic all voids and crevices between the sole and theshoe bottom are nlled. with the result that the plastic when hardened isa supporter for the entire arch of the shoe.

The plastic shank piece is given the decreased radius oi curvature asillustrated by Fig. 3 for the purpose or bowing the sole I9substantially outward as illustrated. Then, when pressure is applied inthe press 20 before the application of heat, the outer edges oi the solegive under the pressure while the center of the sole is supportedagainst movement by the shank piece ll and the strip Il. This causes theshank portion of the sole to break" so that its outer edges retain theirincreased curvature when the pressure is released so that they pressagainst the welt of the shoe, and improve the appearance of the shoe.

The strip il preferably is of metal so that it acts as a free electrodebetween the two main electrodes for increasing the heat for melting theplastic shank piece.

The strip Il may be omitted vif the plastic selected for the shank pieceis rigid enough to retain its curvature under the described pressure.

The shank piece I1 may be any suitable thermoplasti'c or thermosettingmaterial such, for example, as vinylite, methyl methacrylate or one ofthe polyvinal acetates.

While one embodiment of the invention has been described for the purposeof illustration, it .should be understood that the invention is notlimited to the exact apparatus and arrangement oi apparatus illustratedas modifications thereof may be suggested by those skilled in the artwithout departure from the essence of the invention.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. The method in shoe manufacture which comprises placing a plasticshank piece upon the shank portion of the bottom of a shoe, placing asole upon said bottom with cement therebetween, pressing said soleagainst said bottom and said shank piece, and subjecting the assembly tothe influence of an electrostatic eld for melting said shank piece andsaid cement.

2. The method in shoe manufacturing which comprises placing a metallicstrip upon the shank portion of the bottomot a shoe. placing a plasticshank piece upon said strip, placing` a sole upon said bottom withcement therebetween, pressing said solo against said bottom and saidshank piece, and subjecting the assembly to the innuence ot' anelectrostatic neld in which said strip acts as an electrode, for meltingsaid shank piece and said cement.

3. The method in shoe manufacture which comprises placing a curved-plastic shank piece upon the curved shank portion of the bottom of ashoe, said shank piece having a radius oi curvature less than that oisaid shank portion, placing a soie upon said bottom with cementtherebetween, pressing said sole against said bottom and said shankpiece, and subjecting the assembly to the influence of anelectrostaticileld for melting said shank piece and said cement.

4. The method in shoe manufacturing which comprises placing a metallicstrip upon the curved shank portion of the bottom of a shoe. said shankpiece having a radius of curvature less than that of said shank portion,placing a curved plastic shank piece upon said strip with said stripincluded within the arc of said shank piece, placing a sole upon saidbottom with cement therebetween, pressing said sole against said bottomand said shank piece, and subjecting the assembly to the influence of anelectrostatic field in which said strip acts as an electrode, formelting said shank piece and said cement.

5. The method in shoe manufacturing which comprise; placing a strip uponthe curved shank portion of the bottom of a shoe, said shank piecehavinga radius of curvature less than that of said shank portion,placing a curved plastic shank piece upon said strip with said stripincluded within the arc of said shank piece, placing a sole upon saidbottom with cement therebetween. pressing said sole against said bottomand said `mank piece, and subjecting the assembly to the influence of anelectrostatic field, for melting said shank piece and said cement.

FRED DAWSON.

